Remote sensing of H2O at 0.94 μm

A H2O vapor remote sensing instrument which could operate in the 0.94 mu m region would have several highly desirable characteristics. Among the characteristics are access to absorption lines with approximately the correct strength and the availability of good detection systems. A good candidate for the laser for such a system is a Nd:garnet laser operating on one of the (4)F(3/)2 to I-4(9/2) transitions. TO make such a system a reality, NASA Langley has investigated compositional tuning to develop a laser at precisely the correct wavelength and methods of improving the efficiency. Both efforts have achieved success. A flashlamp pumped Nd:YAG laser operating at room temperature on the 0.946 mu m transition has achieved a threshold of 12 J and a slope efficiency of 0.009.